1. Field of the Invention
The present invention relates to a sensor holding apparatus that holds a sensor such that the sensor touches an object at a predetermined position in a three-dimensional space.
2. Related Art Statement
There is a need to hold, at an appropriate position, a sensor such that the sensor lightly contacts, i.e., touches an object. The sensor is, e.g., an ultrasonic sensor that touches skin and detects an image under the skin; a photoelectric-pulse-wave sensor that touches skin and detects a photoelectric pulse wave; or a pressure-pulse-wave sensor that touches skin right above an artery and detects a pressure pulse wave from the artery.
To meet the above-identified need, Patent Document 1 (Japanese Patent Application Publication No. 2000-254105) proposes a sensor holding apparatus that holds a sensor such that the sensor contacts a specific portion of skin of a living being. However, in this sensor holding apparatus, a belt wound around an arm of the living being is utilized to press the sensor against the skin. Therefore, this apparatus suffers the disadvantage that the contact pressure is too high and the cross-sectional shape of the underlying blood vessel is deformed. In addition, this apparatus suffers another disadvantage that the sensor cannot easily be moved on the skin surface to seek a target tissue.
Meanwhile, Patent Document 2 (Japanese Patent Application Publication No. 1(1989)-155828) proposes a sensor holding apparatus that holds, without using a belt, a sensor such that the sensor is positioned relative to a specific portion of skin of a living being, without being contacted with the skin. Therefore, this sensor holding apparatus can be used to hold the sensor such that the sensor lightly contacts, i.e., touches the skin.